This invention relates to a guidance device which can be utilized in the alignment of two objects such as vehicles. More specifically, this invention relates to a device for aiding an individual operator in backing a towing vehicle into perfect alignment with a trailer for subsequent connection of the trailer to the vehicle. Additionally, the device may be provided with means to enable the operator to check various electrical systems of the towing vehicle and trailer such as lights and electrically operated brakes.
Generally, the problems accompanying the connection of a trailer to a vehicle arise when the weight of the trailer is such that the tongue of the trailer cannot be moved without great difficulty. This situation requires that the vehicle be backed into perfect alignment with the tongue of the trailer in order to make the connection by lowering the tongue of the trailer onto the ball of the vehicle hitch. Inasmuch as the driver of the vehicle cannot see the hitching device on the vehicle, it is very difficult, if not impossible, to back the vehicle into proper alignment to make the necessary connection.
This has resulted in the coordinating of the efforts of two persons to connect the vehicle to the trailer. One person backs the vehicle and the other person positions himself so that he can visually guide the vehicle operator into the proper alignment for connecting the trailer to the vehicle.
Many times, however, it is inconvenient to find the second person to perform the visual guiding and even then the driver and the guider may have considerable difficulty in coordinating their efforts and signals so as to effect proper alignment of the vehicle and the trailer. The second person is usually necessary also to indicate the operability of various electrical systems which are activated by the driver.
To overcome the difficulties of alignment, devices have long been sought which would enable the driver to make the connection without the assistance of another person. One of the first methods of accomplishing this was to mount a swivel wheel on the tongue of the trailer so that the vehicle may be backed to within some small distance of the trailer by approximating the position of the tongue relative to the ball of the hitch. Thereafter, the trailer tongue was moved over the ball for connection. This method was only effective so long as the tongue wheel rested upon a hard, smooth surface and the tongue weight was not too great. Unfortunately, the trailer tongue usually does not rest upon such a surface and therefore it is very difficult accurately to move the trailer tongue into place over the hitch ball.
Another prior art device utilizes a mirror or combination of flat and convex mirrors positioned above the tongue at a sufficient height to allow the driver visually to guide the vehicle into alignment with the tongue. When using two mirrors, the flat mirror is angled to provide visual contact at close range while the convex mirror is used to provide long range visual contact. This type of device has the disadvantage of often confusing the driver regarding the direction he must turn the steering wheel because of the reversed image in the mirror, thereby requiring considerable practice and skill to use the device effectively. Also, the image in the convex mirror is inherently small and distorted, further complicating its use. And, in darkness, it becomes difficult if not impossible to use such an arrangement.
Another device known in the prior art utilizes indicator sticks to translate the relative positions of the hitch ball and the tongue to the line of sight of the driver. A stick is attached to the tongue and plumbed so that the end of the stick is directly over the coupling assembly of the tongue. Another stick is attached to the vehicle and plumbed so its end is directly over the hitch ball. Thereafter, the vehicle may be backed into alignment by sighting the relation of the ends of the two sticks until they just meet. This device like the mirrors has the drawbacks of confusing the driver and being very difficult to use in darkness.
A device which has very limited usefulness employs steel plates mounted at 45.degree. angles from the hitch ball, similar to the fifth wheel of a tractor, to guide the tongue into position over the ball. This device contemplates that the driver is capable of directing the ball to within a few inches either way of the tongue and that the tongue will give enough to affect alignment for subsequent connection of the trailer to the vehicle. This device has the obvious disadvantages of being of no use until the vehicle and the trailer are within relatively close relation to one another.